CA2050947A1

CA2050947A1 - Electrophotographic, peel-apart color proofing system

Info

Publication number: CA2050947A1
Application number: CA 2050947
Authority: CA
Inventors: Stephan J. W. Platzer; Robert J. Von Trebra; Douglas A. Seeley; Sonya Y. Shaw
Original assignee: Individual
Current assignee: CNA Holdings LLC
Priority date: 1990-09-10
Filing date: 1991-09-09
Publication date: 1992-03-11
Also published as: JPH0695367A; AU8368191A

Abstract

Abstract of the Disclosure This invention relates to an electrophotographic, peel-apart color proofing film which, upon exposure to an actinic radiation source through a screened image, can accurately reproduce an image. The construction is useful as a color proofing film which can be employed to accurately predict the image quality from a lithographic printing process. The image is produced by forming a composite of a receiver base, adhesive layer, photosensitive diazo, diazide or photopolymerizable layer, electrically conducting layer and photoconductor layer. Upon charging, laser exposure, toning, fixing and actinic radiation exposure, an image appears on the receiver base after dry peel apart development.

Description

Backqround of the Inyention The present invention relates to color proofing films. In particular, it relates to an electrophotographic color proofing system wherein the color image is produced by peel development.

In the color printing field, it is desirable to produce a multicolor proof to assist the printer prior to producing lithographic plates and printing with them. The proof should reproduce the color quality that will be obtained during the printing process. The proof must be a consistent duplicate of the desired halftone image. Visual examination of the color proof should show the color rendition to be expected from press printing and any defects in the images which might need to be altered before making the printing plates.

Color proofing sheets for multicolored printing can be made by using a printing pre~s or proof press. This requires that all of the actual printing steps be performed. However, this conventional method of color proofing is costly and time consuming.

Photoimaging processes can also be used to produce color proofs.
There are two general types of photoimaging methods: namely the overlay type and the single sheet type.

': . - ', ~. :
:
. . ,~

,~t,~,~,j,t,, In the overlay type of color proofing method, separate images are produced on independent transparent plastic supports. A
plurality of such supports carrying images of the corresponding colors are then superimposed upon each other over a white sheet to produce a color proofing composite. The primary advantage of the overlay method is that proofs can be made quickly and can serve as a progressive proof by combining any two or more colors in register. However, this type of color proofing method has the disadvantage that the superimposed plastic supports tend to darken the color proofing sheet. As a result, the impression of the color proofing composite thus prepared is vastly different from that of copies actually obtained with conventional printing presses. Examples of such overlay approaches are contained in U.S. Pat. Nos. 3,136,637; 3,211,553; and 3,326,682.

In the single sheet type of color proofing method, a color proofing sheet is prepared by successively producing images of different colors on a single receiver sheet without superimposed plastic supports. This can be accomplished by sequentially applying colorants or colored, photosensitive layers to a single opaque support. This method more closely resembles the actual printing process and eliminates the color distortion inherent in the overlay system. Examples of such single sheet approaches are contained in U.S. Pat. Nos. 3,671,236s 4,260,673: 4,656,114;
4,659,642: and 4,808,508.

The photoimaging processes used for color proofinq generally require an aqueous development step, as given in the above examples. However, a dry, peel apart method can be employed instead of a wet development step. Examples of such peel apart approaches for an overlay proof are contained in U.S. Pat. No.
4,316,951. Examples of such dry development approaches for a single sheet proof are contained in U.S. Pat. Nos . 4,356,253 and 4,895,787.

The above mentioned elements which can be peel developed are based on photopolymerizable layers. A peel differentiation is obtained after exposure. Other peel developable imaging systems are also known. Some are based on o-quinone diazides, as exemplified in U.S. Pat. No. 4,334,006, or on diazonium salts, as exemplified in U.S. Pat. No. 4,520,094.

Color separations in the form of screened or unscreened negative or positive films are normally used to expose the photosensitive layers in proof elements and in printing plates. However, images can also be scanned with the reculting information stored as digital data. This information can be edited on a cathode ray tube display device as needed and then used to directly expose the proof elements and printing plates without the u~age of any negative or positive films.

~.J ' ~ f The electrophotographic method is suitable for exposures using digital information. It can be used to produce printing plates, as shown in U.s. Pat. No. 4,680,244. This method can also be used to produce color proofs, as shown in U.S. Pat. Nos.
4,358,195 and 4,686,163. The materials consist of at least a photoconductive layer and a conductive layer. They are electrically charged, exposed with a modulated laser light beam, developed with a liquid or solid toner, and heat fixed. The electrophotographic color proofing systems which are described in the above mentioned patents require different colored toners, namely cyan, yellow, magenta, and black. Also, the consistency of the toner density on the proof varies with variations in charge density, temperature, and humidity. These special toners and toner inconsistencies are two major disadvantages to these color proofing systems.

In the present inventlon, one produces an electrophotographic color proofing article. The element sequentlally comprises a photoconductive layer, an electrically conductive layer, a transparent support, and a colored photosensitive layer. In one embodiment of the invention, the photosensitive layer is divided into two parts. In another embodiment, an adhesive layer is in contact with tha photosensitive layer. The element is proce~sed by laminating the element to a receiver base:
electrophotographically fGrming a toner mask on the photoconductive surface, blankat exposing the photosensitive ~ ~ ? ' ~
layer through the mask and support: and removing the nonimage areas with the support, photoconductive layer, and electrically conductive layer. The toned mask provides for a good final dot reproduction. The process is repeated for all of the colored layers. The method produces a full colored reproduction on a single sheet.

The advantages of the presPnt invention are that (1) both normal actinic light and digitally generated light can be used to expose the article, (2) image formation is by a convenient peel apart process, (3) only one toner is required for the different colored articles, and (4) color density is consistent due to the precoated colored layers. Traditional color proofing films have been used to check the quality of the color separation films which will ultimately be used to make the printing plates. This invention is suited for digital color proofing in which proofs can be made directly from digital information using a laser to write the image data directly to the film. Color separation films need not be made, and so a purpose of the invention would be to proof the digital data and the data output device directly.
Traditional color proofing systems cannot proof digital data.

Brief Descri~ion of the Drawings Figure 1 shows the electrophotographic color proofing article of the invention which includes a photoconductive layer, electrically conductive layer, transparent support, and colored photosensitive layer.

Figure 2 shows an embodiment of the invention which includes a photoconductive layer, electrically conductive layer, transparent support, colored photosensitive layer, and adhesive layer.

Figure 3 shows another embodiment of the invention which includes a photoconductive layer, electrically conductive layer, transparent support, photopolymerizable layer, colored photosensitive layer, and adhesive.

summary of the Invention The present invention provides an electrophotographic color proofing article which comprises:
(i) a transparent support; and (ii) a transparent, electrically conductive layer on one side of said support; and tiii) a transparent, photoconductive layer on said conductive layer; and (ivJ a colored photosensitive layer on the other side of said support; said colored photosensitive layer comprising at least one colorant, at least one photosensitive component, and at least one binder resin; said photosensitive component selected from the group consisting of polymeric diazonium salts, o - quinone diazides, and photopolymerizable compositions: said photopolymerizable compositions comprising both a photoinitiator and a free radical polymerizable component having at least one ethylenically unsaturated group; wherein said photosensitive component is present in sufficient amount to provide image differentiation when the composition is imagewise exposed to actinic radiation through said photoconductive layer, said conductive layer, and said support; wherein said colorant is present in an amount sufficient to uniformly color the layer; and wherein said binder resin is present in sufficient amount to bind the composition componants into a uniform film: and (v) an optional adhesive layer directly adhered to said colored photosensitive layer, which adhesive layer comprises a J
thermoplastic resin which has a Tg in the range of from about 25c to about 100C.

I'he present invention also provides an electrophotographic color proofing article which comprises:
(i) a transparent support; and ~ii) a transparent, electrically conductive layer on one side of said support; and (iii) a transparent, photoconductive layer on said conductive layer; and (iv) a photopolymerizable composition layer on the other side of said support, which photopolymerizable layer comprises a photoinitiator, a free radical polymerizable component having at least one ethylenically unsaturated group, and a binder resin;
wherein said photoinitiator is present in sufficient amount to initiate the free radical polymerization of said polymerizable component upon exposure to actinic radiation through said photoconductive layer, said conductive layer, and said support;
wherein said polymerizable component is present in sufficient amount to provide image differentiation when the composition layer is imagewise expo~ed to actinic radiation: and wherein said binder resin is present in sufficient amount to bind the composition components into a uniform film; and (v) a colored photosensitive layer on ~aid photopolymerizable composition layer; said colored photosensitive layer comprising at least one colorant, at least one photosensitive component, and ,, ~ . .. 3 ~ .

at least one binder resin: said photosensitive component selected from the group consisting of polymeric diazonium salts, o -quinone diazides, and photopolymerizable compositions; said photopolymerizable compositions comprising both a photoinitiator and a free radical polymerizable component having at least one ethylenically unsaturated group wherein said photosensitive component is present in sufficient amount to provide image dlfferentiation when the composition is imagewise exposed to actinic radiation through said photoconductive layer, said conductive layer, and said support: wherein said colorant is present in an amount sufficient to uniformly color the layer; and wherein said binder resin is present in sufficient amount to bind the composition components into a uniform film: and (vi) an optional adhesive layer directly adhered to said colored photosensitive layer, which adhesive layer comprises a thermoplastic resin which has a Tg in the range of from about 25C to about 100C.

The present invention further provides a method for producing an image which comprises:
(A) providing one of the aforesaid electrophotographic color proofing articles; and (B) either ~i) laminating at elevated temperature and pressure said electrophotographic article to a receiver sheet via the colored photosensitive layer or the optional adhesive layer; and , ~
electrically charging the photoconductive layer cf said electrophotographic article; and imagewise exposing said charged photoconductive layer to radiation to which the colored photosensitive layer and the optional photopolymerizable layer are not sensitive; and toning the photoconductive layer with a t:oner which is substantially opaque to actinic radiation used to expose said colored photosensitive layer and said optional photopolymerizable layer; and optionally fixing at elevated temperature the imaged toner on said photoconductive layer: and exposing said colored photosensitive layer and said optional photopolymerizable layer to actinic radiation through the toned photoconductive layer, conductive layer, and support; or (ii) electrically charging the photoconductive layer of said electrophotographic article; and imagewise exposing said charged photoconductive layer to radiation to which the colored photosensitive layer and the optional photopolymerizable layer are not sQnsitive; and toning the photoconductive layer with a toner which is substantially opaque to actinic radiation used to expose said colored photosensitive layer and said optional photopolymerizable layer; and optionally fixing at elevated temperature the imaged toner on said photoconductive layer; and exposlng said colored photosensitive layer and said optional photopolymerizable layer to actinic radiation through the toned photoconductive layer, conductive layer, and support: and laminating at elevated temperature and pressure the imaged electrophotographic article to a receiver sheet via the exposed colored photosensitive layer or the optional adhesive layer: and (C) peeling off the support along with the toned photoconductive layer, conductive layer, optional photopolymerizable layer, and nonimage areas of the colored photosensitive layer, leaving the image areas of the colored photosensitive layer and the optional adhesive on the receiver sheet.

In the most preferred embodiment, the method further comprises repeating steps (A) through (C) at least once wherein another electrophotographic article according to step tA) having at least one different colorant is laminated to the image produced from the previous electrophotographic article.

Detailed Description~ o~ ~he Prefer~ed ~m~odime~t In the usual full color proofing guide, four distinct colored images are formed, namely magenta, cyan, yellow, and black. When the images are superimposed upon each other, a simulated full color reproduction results. As hereinbefore described, one begins the process of the present invention by preparing an electrophotographic article which has a transparent support. An electrically conductive layer is on one side oP the support and a photoconductive layer is on the electrically conductive layer. A
colored photosensitive layer containing a photosensitive component, and binder re~in is on the other side of the support.
There is an optional adhesive layer on the colored photosensitive layer. In one embodiment of the invention, two photosensitive layers substitute for the one photosensitive layer. In this case, a photopolymerizable layer is disposed adjacent to the support, and a colored photosensitive layer is on the photopolymerizable layer.

In the preferred embodiment, the support may be composed of any suitable flexible sheet material provided it is transparent to the actinic radiation for the colored photosensitive layer and optional photopolymerizable layer. It should also preferably be dimensionally stable when undergoing the herein specified lamination and peeling processes. That is, it should have substantially no change in dimensions under heating in the range from approximately 60C to 120C during lamination. One preferred material is polyethylene terephthalate. In the preferred embodiment it has a thickness of from about 25um to about 250um, a more preferred thickness is from about 50um to about 125um and most preferably from about 50um to about 75um.
Suitable films nonexclusively include Melinex 054, 504, 505, and 582 available from ICI, and Hostaphan 4400, 4500, and 4540 available from Hoechst Celanese corporation. The surface of the support may be smooth or it may be provided with a matte texture as with Melinex 475. A smooth surface is preferred because a rough surface scatters the actinic radiation and thereby reduces the resolution capability of the element. Other supports may be other types of polyesters, polycarbonates, polystyrenes, cellulose acetates, polyvinyl acetates, polyethylenes, polyamides, and the like provided they are substantially transparent. One or both sides of the support can be modified for proper attachment of the electrically conductive layer and of the colored photosensitive layer and optional photopolymerizable layer.

One surface of the support must have a transparent, electrically conductive material thereon. Such include vapor deposited metals, such as aluminum, copper, zinc, ~ilver, nickel, chromium, SnO2, or In203 among others. Vapor deposition techniques are well known in the art. The electrically conductive surface, when grounded, is used to selectively dissipate the electrostatic charge applied to the photoconductive layer. Since such ;J 1.,~ ?
electrically conductive materials can be vacuum deposited on the transparent film support as a very thin transparent layer, the underlying light sensitive layer can be exposed to light through the electrically conductive layer and transpaxent film support.
Particularly useful electrically conductive supports can be prepared by coating electrically conductive layers prepared by dispersing electrically conductive compounds (e.g., SnO2 and In2O3) or metallic powders in a solvent, onto a support material such as polyethylene terephthalate. These electrically conductive layers are described in U.S. Patent Nos. 2,901,348 and 3,245,833.

Other useful electrically conductive layers include those prepared by the vacuum deposition of compositions consisting substantially of at least ons protective inorganic oxide and from about 30 to 70% by weight of at least one electrically conductive metal based on the weight of electrically conductive layer. For example, electrically conductive layers prepared by vacuum deposition are disclosed in U.S. Patent No. 3,880,657.
Similarly, a suitable electrically conductive coated product can be preparèd using the sodium salt of carboxy ester lactone of maleic anhydrides and a vinyl acetate polymer. Electrically conductive layers of that type, and methods of production and use thereof, are disclosed in U.S. Patent Nos. 3,007,901 and 3,262,807.

r Photoconductors the~selves are also well known in the art.
Organic photoconductors are preferred for the instant invention.
The photoconductive compositions for use in the electrophotographic light-sensitive material of the invention preferably comprises a photoconductive substance and an electrically insulative, film-forming binder substance. Such photoconductive substances include a wide variety of organic and inorganic photoconductive substances, including organometallic compounds. The photoconductive composition can contain various sensitizing materials such as spectral sensitizing dyes and chemical sensitizers. In general, a typical photoconductive composition of the invention contains the photoconductive substance in the amount of at least 1% by weight based on the total weight of the photoconductive composition when dry.
Preferably the photoconductive substance is contained in the amount of at least about 15% by weight based on the total weight of the photoconductive composition.

The upper limit of the amount of the photoconductive substance in a qiven photoconductive composition varies in a wide range depending on the compatibility of the sensitivity of the photoconductor with the specific binder component. When a polymeric photoconductive substance is used as a photoconductor, the photoconductive composition can be composed of the pol,vmeric photoconductive substance alone since it also functions as a binder because of its polymeric properties. In many cases, however, it is desirable to incorporate a specially selected binder into the photoconductor composition to provide useful electrically insulative properties and film-forming properties even in the case of using polymeric photoconductive substances in the photoconductive composition for the electrophotoconductive light-sensitive material of the invention. The amount of the polymeric binder component used is within the range of from about 10% to 85% by weight based on the total dry weight of the photoconductive composition.

A wide variety of photoconductors including inorganic, organic, and polymeric photoconductive substances, including organometallic compounds can be used in the photoconductive composition of the invention. These compound are well known in the art, and examples nonexclusively include:

Zinc oxide, lead oxide, selenium oxide, granular organic pigments, e.g., indigo and phthalocyanine pigments, and organic compounds including organometallic compounds as polymeric organic photoconductors.

Examples of such photoconductive substances are described in the report titled "Electrophotographic Elements, Materials and Processes", appearing in Research Disclosure, Vol. 109, page 61, May 1973. ~

r f ~ J ' ~ t Photoconductive substances which are preferably used in the invention are polymeric organic photoconductive s~bstances containing a polycyclic or heterocyclic aromatic ring. These polymeric organic photoconductors containing a polycyclic or heterocyclic aromatic ring are vinyl polymer type polymers containing a electron system in the main or side chain thereof.

Typical pi electron systems contained in polymeric organic photoconductors include polycyclic aromatic hydrocarbons, such as naphthalene, anthracene, pyrene, perylene, acenaphthene, phenylanthracene, and diphenylanthracene, heterocyclic aromatic compounds, such as carbazole, indole, acridine, 2-phenylindole, and N-phenylcarbazole, and their halogen or lower alkyl having 1 to 5 carbon atoms-substituted derivatives. Representative examples are given below.

Polymers or copolymers such as vinyl polymers, e.g., polyvinyl naphthalene, polyvinyl anthracene, polyvinyl pyrene, polyvinyl perylene, polyacenaphthene, polystyryl anthracene, polyvinyl carbazole, polyvinyl indole and polyvinyl acridine; vinyl copolymers, e.g., copolymers obtained by the reaction between methyl methacrylate, methyl acrylate or acrylamide and at least one of the above described vinyl compounds; vinyl ether polymers, e.g., polyanthryl methylvinyl ether, polypyrenyl methylvinyl ether, polycarbazolyl ethylvinyl ether, and polyindolyl ethylvinyl ether; epoxy resins, e.g., polyglycidyl carbazole . 3 polyglycidyl indole, and poly p-glycidyl anthrylbenzene;
poly3crylates or polymethacryla~es contalning a pi electron system as described above as a substitution group; and cc~ndensation polymers of the above described pi electron system compounds and formaldehyde.

0~ these compounds, poly-N-vinyl carbazole and poly-N-vinyl carbazoles su~stituted on a carbazole ring by, for example, an aryl group having 6 to 12 carbon atoms, an alkaryl group having 7 to 20 carbon atoms, an amino group, an alkylamino group having 1 to 10 carbons atoms, a dialkylamino group having 2 to 10 carbon atoms, an arylamino group having 6 to 12 carbon atoms, a diarylamino group having 12 to 18 carbon atoms, a N-alkyl-N-arylamino group alkyl having 1 to 10 carbon atoms and aryl group having 6 to 12 carbon atoms, a nitro group, and a halogen atom (these poly-N-vinyl carbazoles are herein referred to as substituted poly.-N-vinyl carbazoles), and N-vinyl carbazole copolymers are preferred.

N-vinylcarbazole copolymers which can be used contain at least 50 mole % of the N-ethylene carbazole constituent repeating unit represented by the general formula:

_f,"_ ~

wherein Z represents the same substituent as described for the above described substituted poly-N-vinyl carbazoles.

Constituent repeating units forming the N-vinyl carbazole copolymers other than the N-vinyl carbazole constituent repeating unit include l-phenylethylene, 1-cyanoethylene, l-cyano-l-methylethylene, l-chloroethylene, l-(alkoxycarbonyl) ethylene, and 1-alkoxycarbonyl-1-methylethylene, which are derived from styrene, acrylonitrile, methacrylonitrile, vinyl chloride, alkyl acrylate, and alkyl methacrylate, respectively, and in which as the alkyl group for the alkoxycarbonyl group, an alkyl group containing from 1 to 18 carbon atoms, e.g., a methyl group, an ethyl group, a hexyl group, a dodecyl group, an octadecyl group, and a 4-methylcyclohexyl group, can be used.

-The photoconductive composition of the invention can be used in a conventional manner. That ls as a dispersion or solution of the photoconductive substance mixed with a binder and coated on the electrically conductive layer.

The photoconductive composition of the invention can be sensitized by adding conventional sensitizers in an effective amount to provide improved electrophotographic sensitivity.
Sensitizing compounds which are useful for various photoconductive compositions can be selected, e.g., from the following compounds.

1 .~ J ;J ~ .t .
various pyrylium dye salts as described in u.s. Patent No.
l,250,615, e.g., pyrylium, bispyrlium, thiapyrylium and selenapyrylium dye salts, 2,6-di-tert-butylthiapyryliUm dye salts as described in Japanese Patent Applications (OPI) 1292~3/80, 12560/81, 105547/79, and 114259/80, fluorenes, e.g., 7,12-dioxo-13-dibenzo(a.h)-fluorene, aromatic nitro compounds as described in U.S. Patent No. 2,610,120, anthrones as described in U.S. Pat.

2,670,284, quinones as described in U.S. Patent No. 2,670,286, benzophenones, e.g., those as described in U.S. Patent No.
2,670,287, thiazoles, e.g., those as described in U.S. Patent No.

3,732,301, cyanine (including carbocyanine), merocyanine, diarylmethane, thiazine, azine, oxazine, xathene, phthalein, acridine, and azoanthraquinone dyes, and mixtures thereof.

In adding such sensitizing compounds to the photoconductive composition of the invention, they are usually mixed in with the other coating ingredients. In accordance with this method, the sensitizlng compound is distributed uniformly in the resulting coating layer. Other methods of adding the sensitizing compound can be used in the practice of the invention~ Of course, it is not necessary to sensitize a layer in which the specific photoconductive substance used shows sufficient sensitivity in a given spectral region without a sensitizer. Addition of the sensitizing compound withln the concentration range of from about 0.001 to 30% by weight, preferably from about 0.005 to 10% by weight, based on the dry weight of the photoconductive , composition, increases the sensitivity, although the optimum concentration varies depending on the types of the phvtoconductive compound and sensitizing compound used.

Of various binders which can be used in the photoconductive composition of the invention, film-forming, hydrophobic polymeric substances having a high di-electric breakdown strength and good electrical insulating properties are preferred for use.

Typical examples of such substances are natural resins, polystyrenes, polymethacrylates, polyolefins, polyvinyl acetals, polyvinyl alcohols, polyamides, phenol-formaldehyde resins, paraffins and mineral waxes.

Various known solvents can be used as solvents or dispersing media for the preparation of the photoconductive composition of the invention. Volatile organic solvents are very effective.
Typical examples of such solvents include aromatic hydrocarbons, e.g., benzene, substituted aromatic hydrocarbons, e.g., toluene, xylene, and mesitylene, ketones, e.g., acetone, and 2-butanone, halogenated aliphatic hydrocarbons, e.g., methylene chloride, chloroform, and ethylene chloride, ethers and cyclic ethers, e.g., tetrahydrofuran, methyl ethyl ether, and ethyl ether, and ~ixtures thereof.

In a particularly preferred embodiment of the invention, the photoconductive composition for use in the electrophotographic article of the invention is a homogeneous organic photoconductive composition containing an electrically insulating, film-forming polymeric binder and an organic photoconductor in the binder in the state of a solid solution. One or more sensitizing compounds, for example, one of pyrylium, bispyrlium, thiapyrylium, and selenapyrylium can be added. The photoconductive composition can be coated with ease using an organic solvent.

On the other side of the transparent support is one or two photosensitive layers. In one embodiment, a single, colored photosensitive layer is used which contains a colorant, and a photosensitive component which may be a photopolymerizable composition, a diazonium salt or o-quinone diazide compound, and a polymeric binder. In another embodiment, two photosensitive layers are used, in which case a photopolymerizable composition is first applied to the support. This photopolymerizable layer contains a photoinitiator, free radical polymerizable compound, and a binder resin. Applied to this photopolymerizable layer is a colored photosensitive layer which contains a colorant, photosensitive compound, and a binder resin.

Tha photopolymerizable layer, when it is used, is applied from a solvent coating composition to the support. Organic solvents are preferred for the photopolymerizable coating because of the diverse solubility characteristics of the various components.
Typical solvents nonexclusively include methyl ethyl ketone, 2-methoxyethanol, 1-methoxy-2-propanol, 4-hydroxy-4-methyl-2-pentanone, tetrahydrofuran, and gamma-butyrolactone.

typical photopolymerizable layer comprises a photopolymerizable monomer, photoinitiator, binder resin, and optional other ingredients known in the art.

The photopolymerizable material preferably comprises a non-gaseous (boiling temperature above 100C at normal atmospheric pressure)~ ethylenically-unsaturated compound containing at least one and preferably at least two terminal unsaturated groups, and being capable of forming a high molecular weight polymer by free radical initiation, chain propagating addition polymerization.
The most preferred compounds are acrylate or methacrylate monomers as are well known in the art. Suitable polymerizable materials nonexclusively include triethylene glycol dimethacrylate, tripropylene glycol diacrylate, tetraethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol dimethacrylate, pentaerytbritol tetraacrylate, trimethylol propane triacrylate, trimethylol propane trimethacrylate, di-pentaervthritol monohydroxypentaacrylate, pentaerythritol triacrylate, bisphenol A ethoxylate dimethacrylate, trimethylolpropane ethoxylate triacrylate, and trimethylolpropane propoxylate triacrylate.

Free radical liberating photoinitiators include any compound which liberates free radicals on stimulation by actinic radiation. Preferred photoinitiators nonexclusively include quinoxaline compounds as described in U. S. Patent No. 3,765,898;
the vicinal poly~etaldonyl compounds in U. S. Patent No.
2,367,660; the alpha-carbonyls in U.S. Patent Nos. 2,367,661 and 2,367,670; the acyloin ethers in U. S. Patent No. 2,448,828; the triarylimidazolyl dimers in U. S. Patent No. 3,479,185; the alpha-hydrocarbon substituted aromatic acyloins in tl. S. Patent No 2,722,512; polynuclear quinones in U. S. Patent Nos. 2,951,75 and 3,046,127; and s-triazines in U. s. Patent No~ 4,656,272.
The most preferred photoinitiators include 2,3-di(4-methoxyphenyl)quinoxaline, 9-phenylacridine, bis(2,4,5-triphenyl)imidazole, bis-trichloromethyl-~-triazine and their derivatives.

The photopolymerizable layer also contains a binder resin which not only determines the hardness and/or flexibility of the coating but is also used to control the dry development. Binder resins found suitable for the layer are polyvinyl acetates, styrene/maleic anhydride copolymers and their half esters;
acrylic polymers and copolymers; polyamides: polyvinyl pyrrolidones: cellulose and its derivatives; phenolic resins; and the like. The most preferred binder resins are polyvinyl acetates and acPtals, such as UCARS from Union Carbide, and polyvi~yl butyral and polyvinyl propional.

Oyes may be included to spectrally sensitize the photoinitiator, s~uch as described in U. S. Patent Nos. 4,282,309 and 4,454,218, and European Patent Applications 0,179,448 and 0,211,615.

Other ingredients which may be present in the photopolymerizable layer are thermal polymerization inhibitors, plasticizers, oligomers, residual solvent~, sur~actants, lnert ~lllers, antihalation agents, hydrogen atom donors, photoactlvators, and optical brightening agents.

In the preferred embodiment, the dry photopolymerizable layer has a coating weight range of from about 0.1 to about 5 g/m2. The more preferred coating weight is from about 0.4 to about 2 g/m2.

In the practice of the present invention, the photopolymerizable monomer component is preferably present in the photosensitive layer in an amount ranging from approximately 10 to 60 % based on the weight of the solids in the layer. A more preferred range is from approximately 15% to 40%.

In khe practice of the present invention, the photoinitiator component is preferably present in the photosensitive layer in an ,,, . j " . ~l j amount ranging from approximately 2 to 30 % based on the weight of the solids in the layer. A more preferred range is from approximately 6% to 20%.

:[n the practice of the present invention, the binder resin component is preferably present in the photosensitive layer in an amount ranging from approximately 10% to 75% based on the weight of the solids in the layer. A more preferred range is from approximately 20% to 50~.

Bonded to the surface of the transparent support, or photopolymerizable layer~ as the case may be, i3 the photosensitive layer. The photosensitive layer broadly comprises a photosensitizer, colorant, binder resin, and other optional ingredients such as plasticizers, stabilizers, surfactants, antistatic compositions, uv absorbers, optical brighteners, inert fillers, photoactivators, spectral sensitizers, antihalation agents, hydrogen atom donors, exposure indicators, polymerization inhibitors and residual coating solvents.

In one embodiment, the photosensitizer is preferably a light sensitive, negative-working polymeric diazonium salt. The most preferred photosensitizer is the polycondensation product of 3-methoxy-4-diazo-diphenyl amine sulfate and 4,4'-bis-methoxy methyl-diphenyl ether, precipitated as mesitylene sulfonate as taught in U.S. Patent No. 3,849,392. Other suitable photosensitizers are taught in U.S. Patent No. 4,436,804. The diazo compou~ds of choice are preferably soluble in organic solvents.

In another embodiment, the photosensitizer is preferably a light sensitive, positive-working o-naphthoquinone diazide. The most preferred photosensitizer is the ester of bis-(3-benzoyl-4,5,6 trihydroxy phenyl)-methane and 2-diazo-1-naphthol-5-sulfonic acid as taught in U.S. Patent No. 4,407,926. Other suitable photosensitizers are taught in U.S. Patent Nos. 3,106,365;
3,148,983; 3,201,239: and 4,266,001. The diazide compounds of choice are preferably soluble in organic solvents.

In the pxeferred embodiment, the photosensitizer is a combination of photoinitiator and photopolymerizable monomer. The photoinitiator is a compound which liberate~ free radicals upon exposure to actinic radiation like mentioned in the description for the photopolymerizable layer. The monomer is a nongaseous, ethylenically unsaturated compound containing at least two terminal unsaturated groups and being capable of forming a high molecular weight polymer by free radical initiation, chain propagating addition polymerization, like mentioned in the description for the photopolymerlzable layer.

Dyes and/or pigments are included in the photosensitive layer to provide color to the image areas. Preferred colorants for this invention are pigments rather than dyes. Light fast colorants are preferred. The pigments are typically dispersed with an organic binder in an organic solvent or mixture of organic solvents. The pigments may be organic or inorganic. They are ground to a small enough particle size to duplicate the particle size and color of equivalent inks. The median diameter is generally less than 1 micrometar.

Nonexclusive examples of colorants usable in the present invention are as follows: Permanent Yellow G (C.I. ~lO9S), Permanent Yellow GR (C.I. 21100), Permanent Yellow DHG (C.I.
21090), Permanent Rubine L6B (C.I. 15850:1), Permanent Pink F3B
(C.I. 12433), Hostaperm Pink E (73915), Hostaperm Red Violet ER
(C.I. 46500), Permanent Carmine F~B (12485), Hostaperm Blue 92G
(C.I. 74160), Hostaperm Blue A2R (C.I. 74160), and Printex 25.
Most of these are products of Hoechst AG. They can be used separately or blended for a desired color.

Binders found suitable for the colored photosensitive layer are styrene/maleic anhydride copolymers and their half esters;
acrylic polymers and copolymers: polyamides: polyvinyl pyrrolidones: cellulose and its derivatives; phenolic resins: and polvvinyl acetals, such as polyvinyl formal, polyvinyl butyral, and polyvinyl propional.

Other ingredients which may be present in the colored photosensitive layer are the acid sta~ilizers, thermal polymerization inhibitors, plasticizers, oligomers, residual solvents, surfactants, lnert fillers, antihalation agents, hydrogen atom donors, photoactivators, and optical brightening agents.

In the practice of the present invention, the binder component is preferably present in the photosensitive layer in an amount sufficient to bind the composition componen~s in a uniform mixture and a uniform film when it is coated on a substrate. It is preferably present in an amount ranging from about 10% to about 80% based on the weight of the solids in the layer. A more preferred range is from about 20% to about 70%.

When a diazonium salt or diazide compound is the photosensitizer component, it is present in the photosensitive layer in an amount of from about 5 to about 70 by weight; or more preferably from about 10 to about 50 by weight.

In the practice of the present invention, the ~olorant component is preferably present in an amount sufficient to uniformly color the photosensitive layer. It is preferably present in an amount ranging from about 5% to about 50% based on the weight of the solids in the layer. A more preferred range i~ from about 10% to about 40%.

;.~ ` .,~ ,' ` . - i Suitable acid stabilizers useful in the photosensitive composition layer include phosphoric, citric, benzoic, m-nitro benzoic, p(p-anilino phenylazo) benzene sulfonic acid, 4,4'-clinitro-2,2'-stilbene disulfonic, itaconic, tartaric, and p-toluene sulfonic acid, and mixtures thereof. Preferably, the acid stabilizer is phosphoric acid.

A plasticizer may also be included in the photosensitive composition layer of this invention to prevent coating brittleness and to keep the composition pliable if desired.
Suitable plasticizers include dibutylphthalate, triarylphosphate and substituted analogs thereof, and preferably dloctylphthalate.

To form the photosensitive composition layer, the composition components may be dissolved in a solvent or mixture of solvents to facilitate application of the composition to the support or to the optional photopolymerizable layer.

Suitable solvents for this purpose may include water, tetrahydrofuran, gamma butyrolactone, glycol ethers such as propylene glycol monomethyl ether and methyl cellosolve, alcohols such as ethanol and n-propanol, and ketones such as methyl ethyl ketone. In general, the solvent system is evaporated from the coating composition once it is applied. However, some insignificant amount of solvent may remain as residue.

In the preferred embodime~t, the photosensitive layer has a coating weight between approximately 0.1 and 5.0g/m2. The most preferred weight is from about 0.5 to 2.og/m2.

The adhesive layer, when it is used, is next applied to the colored photosensitive layer. The purpose of the adhesive layer on the photosensitive layer is to aid in the transfer of the photosensitive layer to a receiver sheet and to protect the integrity of underlying, previous formed images during dry development of subsequent layer or layers. It may be applied to the photosensitive layer in several different ways. It can be coated directly onto the photosensitive layer out of organic or aqueous based solvent mixtures, or it can be applied by hot melt extrusion, lamination, or coating. The adhesive layer preferably comprises a ma;or amount of one or more thermoplastic polymers and may optionally contain such other desired components as uv absorbers, antistatic compositions, optical brighteners, inert fillers, and plasticizers. Suitable polymers nonexclusively include vinyl acetal resins such as Butvar ~-79 available from Monsanto: acrylic resins such as Elvacite 2044 available from DuPont: ethylene resins such as Elvax 210 available from DuPont;
and vinyl chloride resins such as Hostaflex CM 133 available from Hoechst AG. Preferably the polymer i8 a vinyl acetate polymer or copolymer. Useful polyvinyl acetates nonexclusively include Mowilith DM-6, DM-22, 30 60 and mixtures thereof, available from j"li,;

ffoechst AG. These are usually dispersed in water, or dissolved in methyl isobutyl ketone or n-butyl acetate or other solvent compositions for coating on a photosensitive layer. It is then dried to a coating weight of from about 2 to about 30g/m2, more preferably from about 4 to about 20g/m2. The layer may optionally contain a uv absorber such as Uvinul D-50 available from GAF. It may also contain a plasticizer such as Resoflex R-296, available from Cambridge Industries. It may also contain antistats, such as Gafac and Gafstat available from GAF. It may also contain other resins such as Nitrocellulose RS 1/2, available from Hercules. The adhesive layer should not be tacky to the touch, durinq storage. The layer should be transferable to a receiver sheet in a temperature range of from about 60C to about 180C, preferably 60C to 120C, more preferably 60C to 100C when laminated with heat and pressure. In the preferrsd embodiment, the thermoplastic polymer or polymers are present in the adhesive layer in an amount of greater than about 50% by weight. The plasticizer may be present in an amount of up to about 30% by weight, the uv absorber up to about 20% by weight, and other resins up to about 50% by weight.

In practice, the above formed electrophotographic article is laminated via the adhesive layer to a receiver sheet. Receiver sheets may comprise virtually any material which can withstand the laminating and dry development processes. White plastic sheets, such as adhesion pretreated polyester Melinex 3020 from ICI, are useful for this purpose. Plastic coated paper sheets, such as poly~thylene coated paper from Schoeller, may also be used. Other bases may include wood, glass, metal, paper and the like.

~hen the optional adhesive layer is not used, the receiver sheet can be pretreated with an adhesive layer. This adhesive layer can be either directly coated on the receiver sheet or coated on a carrier with a release surface and then transferred to ths receiver sheet.

Lamination may be conducted by putting the adhesive layer of the electrophotographic article in contact with the receiver base and then introducing the materials into the nip of a pair of heated laminating rollers under suitable pressure. Suitable laminating temperatures usually range from approximately 60 C to 120 C, preferably from 70 C to 100 C. The photoconductive layer is then overall electrostatically charged and imagewise exposed, preferable via a laser, such as an argon laser. Essentially, any known technique of conventional electrophotographic process may be employed. Those generally use a process comprising charging, exposing, developing and fixing steps. The production of images by electrophotographic means may be carried out as follows.

The electrically conductive layer is first grounded. The photoconductive surface is brought into the vicinity of an electrostatic char~inq device to provide an overall uniform electrostatic charge thereon. The charging device may comprise an array of pointed electrodes mounted on a movable insulated device so that it can be passed back and forth over the grounded coated metal film. A high voltage D.C. source is connected to the charging device to provide the necessary charge on the film.
The voltage should be sufficient to cause a corona discharge adjacent to the electrodes. The apparatus and process may produce an overall negative or positive charge, depending on the polarity of the electrodes with respect to the metal. The selection of polarity is dependent upon the toner developer employed in the process. When the photoconductive layer has been provided with an electrostatic charge by means o~, for example, a corona discharge with a charging apparatus maintained at 6000-7000 volts, the photoconductor layer is exposed to actinic light through a master, by projection or by laser to form an electrostatic pattern corresponding to the desired image applied by causing the electrostatic charge to leak away on the areas of the photoconductive layer struck by light. Wherever the light strikes the surface of the photoconductive coating, the electrostatic charge thereon is reduced in direct proportion to the light received. This leaves an electrostatic image or pattern of charges corresponding to the light and dark portions of original image. In one example, a positivQ charge is accumulated and its potential reaches 150-600 V. by passing the photosensitive member below the corona discharger charged with +6KV in the dark several times. Then, from an appropriate light source such as a laser or tungsten lamp, actinic light is patternwise projected onto the charged surPace. The electric charge at the exposed regions is thus neutralized. The latent image thus formed is developed with a charged toner by a magnetic brush or cascade developinq method to produce the image. This image may be fixed by heating or passing it through an appropriate solvent vapor. A liquid developing method may also be used. The toned image is used as a photomask for the exposure of the underlying colored photosensitive layer or combination photopolymerizable layer and colored photosensitive layer.
Therefore, the toner must be substantially opaque to the actinic radiation to be used in the second exposure step.

The colored photosensitive layer, or combination colored photosensitive layer and photopolymerizable layer, is then simultaneously exposed by means well known in the art through the formed toner mask conductive layer and transparent support. This second exposure may be conducted by exposure to actinic radiation from a light source such as mercury vapor discharge lamps or metal halide lamps. Other radiation sources, such as carbon arc, pulsed xenon, and lasers, may also be used.

After the second exposure, a positive image is formed on the receiver sheet by stripping off the transparent support from the receiver sheet at room temperature with a steady, continuous motion. No devices are necessary to hold down the receiver base during stripping because only moderate manual peeling forces are ~eeded to separate the materials. The preferred peel angle relative to the peel direction is greater than 90~ The clelamination leaves the nonimage areas of the colored photosensitive layer attached to the transparent support or photopolymerizable layer. The toned photoconductive layer and conductive layer are also removed with the transparent support.
The image areas of the colored photosensitive layer and optional adhesive layer remain on the receiver sheet. Thus, a colored image is formed on the receiver sheet. At this time, the image may be postexposed to destroy any residual nonexposed photosensitizer present in the image.

To attain a multicolored image, another electrophotographic element is laminated to the first image on the same receiver sheet. The second element preferably has a different color than the first. After lamination to the same receiver, charging, exposing, tonin~, developing, exposing and peel apart are conducted again as was done with the first article. The second image and optional adhesive layer remain with the first image. A
third and a fourth image may be added in a manner similar to that used to produce the second image. In the usual case, four colored layers are employed to produce a full color reproduction of a desired image.

f`~ ,; ~ ,, ~ `, . . ;
A matte finish of the final image may bs obtained by embossing the shiny, top surface of the image with a matte material, such as Melinex 377 from ICI. This is done by laminating together the final image and matte material. The matte material is then generally removed after lamination. The advantage ot this method is that the finish of the final proof can be determined by careful selection of the matting material.

The final four color proof may be given a uniform, blanket exposure to photoharden the nonexposed, colored areas on the receiver base. A protective layer may also be laminated on top of the last dry developed layer.

The following nonlimiting examples serve to illustrate the present invention.

EXAMPLE

A series of electrophotographic articles as schematically shown in Figure 2 are produced in which an adhesive layer is on different colored photosensitive layers.

Kodak Ektavolt SO101 is an electrophotographic composite available from Kodak. It is comprised of four layers; a photoconductive layer, conductive layer, transparent support, and adhesion promoting subbing layer. The subbing layer is washed off with methyl ethyl ketone for the present invention. The support of the composite without the subbing layer is coated with the colored photosensitive solutions.

The formulations for the four different colored photosensitive solutions include the following ingredients in parts by weight, as indicated.

Cyan Yellow Magenta Black Tetrahydrofuran 200 200 200 200 4-Hydroxy-4-methyl-2-pentanone 150 150 150 150 l-Methoxy-2-propanol 444 465 489 490 gamma-Butyrolactone 44 65 89 so Formvar 12/85 6 13 18 9 Di-pentaerythritol 8 12 8 12 monohydroxy pentaacrylate 2,3-Di(4-methoxyphenyl~quinoxaline 4 4 4 4 Hostaperm B2G 7 - - -Permanent Yellow GR - 7 Permanent Red FBB - - 12 Printex 25 - - - 11 The pigments are dispersed in some of the binder resin and solvents. They are ground to the proper particle size for the correct transparency. The median diameter is less than 0.2 micrometers. The ingredients are thoroughly mixed before being coated on the support of the Ektavolt composite. The coatings are dried at 93C to give optical densities of 1.3, 0.9, 1.3, and 1.6 for cyan, yellow, magenta, and black, respectively.

The formulation for the adhesive layer includes the following ingredients in parts by weight, as indicated.

n-sutyl acetate 78 Reseflex R-296 Butvar B76 Mowilith 30 20 Ihe adhesive ingredients are thoroughly mixed and coated onto a 67 um thick film of Melinex 516, which i5 a slip treated film available from ICI. The coating is dried at 93C to a coating weight of 12 g/m2. The adhesive layer is then applied to the four different photosensitive layers by laminating the two types of materials together at 85C. The film carrier for the adhesive is removed, leaving an adhesive layer on each photosensitive layer.

The cyan electrophotographic article, is laminated at 85C via the adhesive layer to a white receiver sheet, that is, 145 um thick Melinex 3020. The transferred electrophotographic article is then electrostatically charged. The photoconductive layer i8 exposed to visible light, to which the photosensitive layer is not sensitive. The latent electrostatic image is then made visible by toning the photoconductive layer with carbon black.
The photosensitive layer is then exposed to ultraviolet light which is attenuated by the carbon black image but is transmitted through the support in the noncarbon black areas. The toned photoconductive layer, conductive layer, and support along with the exposed colored areas of the photosensitive layer are peeled off the receiver sheet after the second exposure. Only the adhesive layer and the nonexposed areas of the photosensitive ~ :J `,,' _3 ~
layer remain on the receiver sheet. Thus, a cyan positive image is obtained.

The yellow electrophotographic article is laminated via its adhesive layer to the cyan image on the receiver sheet. The yellow article is then electrostatically charged, imagewise exposed with visible light, toned with carbon black, blanket exposed with ultraviolet light through the carbon black mask, and peeled apart. The adhesive layer and the nonexposed areas of tha yellow photosensitive layer remain on the cyan image. Thus, a yellow image and a cyan image are obtained on the same receiver sheet.

The process is repeated for the magenta photographic article and then for the black article. A full four color reproduction is produced which gives an accurate representation of the original colored image. The resolving power for equal lines and spaces using these electrophotographic articles is 25 micrometers. The dot reproduction is 4 to 96 with a 60 lines/cm screen.

EXAMP~

A series of electrophotographic articles as schematically shown in Figure 1 are producad in which dif~erent colored photosensitive layers are iirst expo~ed and then laminated to adheslve layers. The subbing layer on the Kodak Ektavolt Solol is removed. The support of the composite without this layer is coated with the colored photosensitive solutions. The formulations for the four different colored photosensitive solutions include the following ingredients in parts by weight, as indicated.
Cyan Yellow Magenta ~lack 2-Methoxyethanol 4100 4100 4650 4100 2 butanone 4100 4099 4648 4100 gamma-Butyrolactone 1000 1000 - 1000 Dimethyl phthalate 75 75 88 75 Dibutyl phthalate 25 25 - 25 p-Toluene sulfonic acid - - 18 35 Scripset 540 333 2~0 315 371 Scripset 550 117 Hydrolyzed Scripset 540 - - 67 Diazo from U.S. Pat 3,849,392133 135 70 200 Hostaperm B2G 117 - - -Permanent Yellow GR - 104 Permanent Red FB~ - - 144 Printex 25 - - - 94 The Scripset resins are available from Monsanto and the SMA resin is available from Arco. The pigments are dispersed in some of the binder resin and solvents. They are ground to the proper particle size for the correct transparency. The median diameter is less than 0.2 micrometers. The ingredients are thoroughly mixed before being coated on the support of the Ektavolt composite. The coatings are dried at 93C to give optical densities of 1.1, 0.9, 1.2, and 1.5 for cyan, yellow, magenta and black respectively. The coating weights are 1.3, 0.9, 1.8 and 1.2 g/m2 respectively.

The formulation for the adhesive layer includes the following ingredients in parts by weight as indicated.

n-butyl acetate 78 Resoflex R-296 Mowilith 60 21 The adhesive ingredients are thoroughly mixed and coated onto Melinex 516. The coating is dried at 93C to a coating weight of 12 g/m2. The adhesive layer is then applied at 85C to a Melinex 3020 receiver sheet. The film carrier for the adhesive is removed, leaving an adhesive layer on the receiver.

The cyan electrophotographic article is electrostatically charged. The photoconductive layer is then exposed to visible light to which the photosensitive layer is not sensitive. The latent electrostatic image is then made visible by toning the photoconductive layer with carbon black. Ths photosensitive layer is then exposed to ultraviolet light through the carbon black mask. The toned photoconductive layer, conductive layer, transpar2nt support and exposed photosensitive layer are laminated at 85C via the photosensitive layer to the adhesive layer on the receiver sheet. The toned layer, conductive layer, and support along with the unexposed colored areas of the photosensitive layer are peeled off the receiver sheet after lamination. Only the adhesive layer and the exposed areas of the photosensitive layer remain on the receiver sheet. Thus a cyan negative image is obtained.

Another adhesive layer is laminated to the cyan image on the receiver sheet. Its film carrier is removed. The yellow electrophotographic article is electrostatically charged, Lmagewise exposed with visible light, toned with carbon black, blanket exposed with ultraviolet light through the carbon black ~ask, laminated to the adheQive on the cyan image, and peel developed. The second adhesive layer and the exposed areas of the yellow photoæensitive layer remain on the cyan image. Thus, a yellow image and a cyan image are obtained on the same receiver sheet.

The process is repeated for the magenta electrophotographic article and then for the black article. A full, four color reproduction is produced which gives an accurate representation of the original colored image.

EXAMpLE 3 A series of electrophotographic articles as shown in Figure 3 are produced in which a photopolymerizable layer is in contact with differen~ colored photosensitive layers. The subbing layer on the Kodak Ektavolt SO101 is removed. The support of the composite without this layer is coated with a photopolymerizable solution. The formulation for the photopolymerizable solution includes the following ingredients in parts by weight, as indicated.

Tetrahydrofuran 200 4-Hydroxy-4-methyl-2-pentanone 150 l-Methoxy 2-propanol 400 gamma-Butyrolactone 50 Mowilith 30 12 Trlmethyl propane triacrylate 8 2,3-Di(4-methoxyphenyl)quinoxaline 4 The photopolymerizable solution is coated and dried on four desubbed Ektavolt supports. The dry coating weight is 2 g/m2.
The formulations for the four different colored photosensitive solutions include the following ingredients in parts by weight, as indicated.
Cyan Yellow Magenta Black Tetrahydrofuran 200 200 200 200 4-Hydroxy-4-methyl-2-pentanone150 150 150 150 1-Methoxy-2-propanol 400 400 400 400 gamma-Butyrolactone 50 50 50 50 2-Butanone 84 89 90 90 Scripset 540 11 6 5 4 Diazo from U.S. Pat. No. 3,849,392 4 2 2 2 Hostaperm B2G 5 - - -Permanent Yellow GR - 5 Permanent Red FBB - - 5 Printex 25 - - - 6 The ingredients are thoroughly mixed before being coated on Melinex 516 sheets. The coatings are dried at 93C to give optical densities of 1.3, 0.9, 1.3, and 1.6 for cyan, yellow, magenta, and black, respectively. The dried coatings are next separately laminated to the four photopolymerizable layers via the colored photosensitive layers. The film carriers for the photosensitive layers are removed.
The formulation for the adhesive layer includes the following ingredients in parts by weight, as indicated.

n-8utyl acetate 78 Re30flex R-296 Mowilith 30 21 The adhesive ingredients are thoroughly mixed and directly coated onto the transferred photosensitive layers. The adhesive coatings are dried at 93C to a coating weight of 12 g/m2.
The magenta electrophotographic article is laminated at 85C via the adhesive layer to a white receiver sheet, that is, Champion Kromekote lS coated paper. The transferred electrophotographic article is then electrostatically charged. The photoconductive layer is exposed to visible light, to which the photopolymerizable layer and colored photosensitive layer are not sensitive. The latent electrostatic image is then made visible by tonlng the photoconductive layer with carbon black. The photopolymerizable layer and photosensitive layer are then simultaneously exposed to ultraviolet light using the carbon black mask. The toned photoconductive layer, conductive layer, transparent support, and photopolymerizable layer along with the exposed colored areas of the colored photosensitive layer are peeled off the receiver sheet after the second exposure. Only the adhesive layer and the nonexposed areas of the colored .

" .J _~ ~

photosensitive layer remain on the receiver sheet. Thus, a magenta positive image is obtained.

The cyan electrophotographic article is laminated via its adhesive layer to the ~agenta image on the receiver sheet. The cyan article is then electrostatically charged, imagewise exposed with visible light, toned with carbon black, blanket exposed with ultraviolet light through the carbon black mask, and peel developed. The adhesive layer and the nonexposed areas of the cyan photosensitive layer remain on the magenta inage. Thus, a magenta image and a cyan image are obtained on the same receiver sheet.

The process is repeated for the yellow electrophotograpAic article and then for the black article. A full, four color reproduction is produced.

EXAMPL~ 4 Polyethylene terephthalate film (PET) which is adhesion promoted on one side and untreated on the other side (Melinex 504 from ICI) is aluminized on the untreated surface to a level such ~hat approximately 50% light transmission is attained.
An organic photoconductor solution is prepared as follows (parts by weight):

Toluene ~.oo 2-Butanone 4.00 gamma-sutyrolactone 2.40 poly(s~vinylcarbazole) 1.60 Eosin Y dye (spirit soluble) 0.1 This solution is coated on the aluminized side of the metallized PET film with a #24 wire wound rod and dried. On the opposite, adhesion promoted slde of the PET film is coated the following photosensitive solution:

Di-pentaerythritol monohydroxy pentaacrylate 8 Tetrahydrofuran 200 4-Hydroxy-4-methyl-2-pentanone150 l-Methoxy-2-propanol 444 gamma-Butyrolactone 44 Formvar 12/85 6.25 2,3-Di(4-methoxyphenyl)-quinoxaline 4 Hostaperm Blue ~2G pigment 6.75 The blue pigment is dispersed in some of the Formvar 12/85 binder resin and solvents. They are ground to the proper particle size for the correct transparency. The median diameter is less than 0.2 micrometers. The ingredients are thoroughly mixed before being coated on the metallized PET film to give an optical density of 1.3.

An adhesive layer is prepared by thoroughly mixing the following ingredients:

n-Butyl acetate 79 Resoflex R-296 Mowilith 30 20 The adhesive solution is coated on 67 micrometer thick Melinex 516~ film and dried at 90C to a coating weight of 12 g/m2. The layer of adhesive is laminated to a white polyester receiver, available from ICI as Melinex 939, using heat and pressure. The Melinex 516 carrier film is then peeled off of the adhesive layer. The colored, photosensitive coated side of the electrophotographic article is laminated to the adhesive layer.
The electrophotographic coating is electrostatically charged and then imagewise exposed with a scanned argon ion laser beam with a wavelength of 488 nm. The latent electrostatic image is developed using a dry black toner (Elfasol EL 07 from Hoechst AG). The photosensitive color coating is exposed to actinic radiation through the PET film, photoconductive coating and toned image. The toned imaye, photoconductive layer, PET support and unexposed colored areas of the photosensitive layer are peeled off of the receiver sheet. Only the adhesive layer and unexposed areas of the photosensitive layer remain on the receiver.

EXA~MPLE 5 A metallized polyester fllm with a visible light transmission of approximately 30% and adhesion treatment on the non-metallized side is coated with the following solution on the metal side:

Parts by Weight Toluene 49.50 Methyl ethyl ketone 25.00 ~utyrolactone 15.00 Poly(9-vinylcarbazo~le) 10.00 Eosin Y dye (Spirit soluble) 0.50 ' liS ~ , This solution is drawn down on the metallized side of the polyester film with a #32 wire wound rod. A colored photosensitive solution is prepared as follows:

Par~s by Weight Di-pentaerythritol monohydroxy pentaacrylate 0.93 Tetrahydrofuran 23.17 4-Hydroxy-4-methyl-2-pentanone 17.38 l-Methoxy-2-propanol 51.45 Formvar 12/85 0.70 2,3-Di(4-methoxyphenyl)quinoxaline 0.46 Hostaperm B2G 0.70 gamma Butyrolactone 5.10 This solution is drawn down on the adhesion promoted non-metallized side of the polyester film with a #12 wire wound rod.
An adhesive film of Mowilith 30 and Resoflex R-296 coated on Melinex 516, as described in Example 2, is laminated to a receiver sheet (Pressmatch Standard Receiver Base from Hoechst Celanese) and the carrier sheet is peeled away. The inventive film is laminated, photosensitive color coat down, to the Mowilith adhesive. The polyvinylcarbazole photoconductor side of the film is electrostatically charged and then exposed with an argon ion laser operating at 488 nm. The latent image is developed by toning with a dry toner (~lfasol EL 07 Developer from Hoechst AG). The film is exposed to actinic radiation in a Ber~ey-Ascor exposure unit with a multi-spectrum bulb through the toned image. After exposure, the metallized polyester film and toner are peeled off to leave a cyan image similar to the toned image.

Claims

1. An electrophotographic color proofing element which comprises:
(i) a transparent support; and (ii) a transparent, electrically conductive layer on one side of said support; and (iii) a transparent, photoconductive layer on said conductive layer; and (iv) a colored photosensitive layer on the other side of said support; said colored photosensitive layer comprising at least one colorant, at least one photosensitive component, and at least one binder resin; said photosensitive component selected from the group consisting of polymeric diazonium salts, o-quinone diazides, and photopolymerizable compositions; said photopolymerizable compositions comprising both a photoinitiator and a free radical polymerizable component having at least one ethylenically unsaturated group; wherein said photosensitive component is present in sufficient amount to provide image differentiation when the composition is imagewise exposed to actinic radiation through said photoconductive layer, said conductive layer, and said support; wherein said colorant is present in an amount sufficient to uniformly color the layer; and wherein said binder resin is present in sufficient amount to bind the composition components into a uniform film; and (v) an optional adhesive layer directly adhered to said colored photosensitive layer, which adhesive layer comprises a thermoplastic resin which has a Tg in the range of from about 25°C to about 100°C.

2. The element of claim 1 wherein the photoconductive layer comprises polyvinyl carbazole.

3. The element of claim 1 wherein said transparent support comprises a material selected from the group consisting of polyesters, polycarbonates, polystyrenes, cellulose acetates, polyvinyl acetates, polyethylenes, polyamides.

4. The element of claim 1 wherein said electrically conductive layer comprises a vapor deposited component selected from the group consisting of aluminum, copper, zinc, silver, nickel, chromium, SnO2 and In2O3.

5. The element of claim 1 wherein said colored photosensitive layer comprises a polymeric diazonium salt which is the polycondensation product of 3-methoxy-4-diazo-diphenyl amine sulfate and 4,4'-bis-methoxy methyl-diphenyl ether precipitated as mesitylene sulfonate.

6. The element of claim 1 wherein said colored photosensitive layer comprises a diazide which is the ester of bis-(3-benzoyl-4,5,6-trihydroxy phenyl)-methane and 2-diazo-1-naphthol-5-sulfonic acid.

7. The element of claim 1 wherein said colored photosensitive layer comprises a photopolymerizable composition which comprises one or more monomers selected from the group consisting of triethylene glycol dimethacrylate, tripropylene glycol diacrylate, tetraethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol dimethacrylate, pentaerythritol tetraacrylate, trimethylol propane triacrylate, trimethylol propane trimethacrylate, di-pentaerythritol monohydroxypentaacrylate, pentaerythritol triacrylate, bisphenol A ethoxylate dimethacrylate, trimethylolpropane ethoxylate triacrylate, and trimethylolpropane propoxylate triacrylate.

8. The element of claim 1 wherein said colored photosensitive layer comprises a photopolymerizable composition which comprises one or more photoinitiators selected from the group consisting of 2,3-di(4-methoxyphenyl)quinoxaline, 9-phenylacridine, bis(2,4,5-triphenyl)imidazole, bis-trichloromethyl-s-triazine and their derivatives.

9. The element of claim 1 wherein said colored photosensitive layer comprises one or more binder resins selected from the group consisting of styrene/maleic anhydride copolymers and their half esters; acrylic polymers and copolymers; polyamides; polyvinyl pyrrolidones; cellulosic resins; phenolic resins; polyvinyl acetals; polyvinyl acetates; and their copolymers.

10. The element of claim 1 wherein said photosensitive layer further comprises one or more ingredients selected from the group consisting of plasticizers, stabilizers, antistatic compositions, uv absorbers, spectral sensitizers, optical brighteners, inert fillers, polymerization inhibitors, oligomers, surfactants, hydrogen atom donors, antihalation agents, and photoactivators.

11. The element of claim 1 wherein said adhesive layer comprises one or more polymers selected from the group consisting of vinyl acetate, vinyl chloride, vinyl acetal, acrylic, and ethylene polymers and copolymers.

12. The element of claim 1 wherein said adhesive layer comprises one or more ingredients selected for the group consisting of plasticizers, uv absorbers, antistatic compositions, inert fillers, antihalation agents, and optical brighteners.

13. An electrophotographic color proofing element which comprises:

(i) a transparent support; and (ii) a transparent, electrically conductive layer on one side of said support; and (iii) a transparent, photoconductive layer on said conductive layer; and (iv) a photopolymerizable composition layer on the other side of said support, which photopolymerizable layer comprises a photoinitiator, a free radical polymerizable component having at least one ethylenically unsaturated group, and a binder resin;
wherein said photoinitiator is present in sufficient amount to initiate the free radical polymerization of said polymerizable component upon exposure to actinic radiation through said photoconductive layer, said conductive layer, and said support; wherein said polymerizable component is present in sufficient amount to provide image differentiation when the composition layer is imagewise exposed to actinic radiation; and wherein said binder resin is present in sufficient amount to bind the composition components into a uniform film; and (v) a colored photosensitive layer on said photopolymerizable composition layer; said colored photosensitive layer comprising at least one colorant, at least one photosensitive component, and at least one binder resin; said photosensitive component selected from the group consisting of polymeric diazonium salts, o-quinone diazides, and photopolymerizable compositions; said photopolymerizable compositions comprising both a photoinitiator and a free-radical polymerizable component having at least one ethylenically unsaturated group; wherein said photosensitive component is present in sufficient amount to provide image differentiation when the composition is imagewise exposed to actinic radiation through said photoconductive layer, said conductive layer, and said support; wherein said colorant is present in an amount sufficient to uniformly color the layer; and wherein said binder resin is present in sufficient amount to bind the composition components into a uniform film; and (vi) an optional adhesive layer directly adhered to said colored photosensitive layer, which adhesive layer comprises a thermoplastic resin which has a Tg in the range of from about 25°C to about 100°C.

14. The element of claim 13 wherein the photoconductive layer comprises polyvinyl carbazole.

15. The element of claim 13 wherein said transparent support comprises a material selected from the group consisting of polyesters, polycarbonates, polystyrenes, cellulose acetates, polyvinyl acetates, polyethylenes, polyamides.

16. The element of claim 13 wherein said electrically conductive layer comprises a vapor deposited component selected from the group consisting of aluminum, copper, zinc, silver, nickel, chromium, SnO2 and In2O3.

17. The element of claim 13 wherein said colored photosensitive layer comprises a polymeric diazonium salt which is the polycondensation product of 3-methoxy-4-diazo-diphenyl amine sulfate and 4,4'-bis-methoxy methyl-diphenyl ether precipitated as mesitylene sulfonate.

18. The element of claim 13 wherein said colored photosensitive layer comprises a diazide which is the ester of bis-(3-benzoyl-4,5,6-trihydroxy phenyl)-methane and 2-diazo-1-naphthol-5-sulfonic acid.

19. The element of claim 13 wherein said colored photosensitive layer comprises a photopolymerizable composition which comprises one or more monomers selected from the group consisting of triethylene glycol dimethacrylate, tripropylene glycol diacrylate, tetraethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol dimethacrylate, pentaerythritol tetraacrylate, trimethylol propane triacrylate, trimethylol propane trimethacrylate, di-pentaerythritol monohydroxypentaacrylate, pentaerythritol triacrylate, bisphenol A ethoxylate dimethacrylate, trimethylolpropane ethoxylate triacrylate, and trimethylolpropane propoxylate triacrylate.

20. The element of claim 13 wherein said colored photosensitive layer comprises a photopolymerizable composition which comprises one or more photoinitiators selected from the group consisting of 2,3-di(4-methoxyphenyl)quinoxaline, 9-phenylacridine, bis(2,4,5-triphenyl)imidazole, bis-trichloromethyl-s-triazine and their derivatives.

21. The element of claim 13 wherein said colored photosensitive layer comprises one or more binder resins selected from the group consisting of styrene/maleic anhydride copolymers and their half esters; acrylic polymers and copolymers; polyamides; polyvinyl pyrrolidones; cellulosic resins; phenolic resins; polyvinyl acetals, polyvinyl acetates and their copolymers.

22. The element of claim 13 wherein said colored photosensitive layer further comprises one or more ingredients selected from the group consisting of plasticizers, stabilizers, antistatic compositions, uv absorbers, spectral sensitizers, optical brighteners, inert fillers, polymerization inhibitors, oligomers, surfactants, hydrogen atom donors, antihalation agents, and photoactivators.

23. The element of claim 13 wherein said photopolymerizable composition layer comprises one or more monomers selected from the group consisting of triethylene glycol dimethacrylate, tripropylene glycol diacrylate, tetraethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol dimethacrylate, pentaerythritol tetraacryiate, trimethylol propane triacrylate, trimethylol propane trimethacrylate, di-pentaerythritol monohydroxypentaacrylate, pentaerythritol triacrylate, bisphenol A ethoxylate dimethacrylate, trimethylolpropane ethoxylate triacrylate, and trimethylolpropane propoxylate triacrylate.

24. The element of claim 13 wherein said photopolymerizable composition layer comprises one or more photoinitiators selected from the group consisting of 2,3-di(4-methoxyphenyl)quinoxaline, 9-phenylacridine, bis(2,4,5-triphenyl)imidazole, bis-trichloromethyl-s-triazine and their derivatives.

25. The element of claim 13 wherein said photopolymerizable composition layer comprises one or more binder resins selected from the group consisting of styrene/maleic anhydride copolymers and their half esters; acrylic polymers and copolymers;
polyamides; polyvinyl pyrrolidones; cellulosic resins; phenolic resins; polyvinyl acetals, polyvinyl acetates and their copolymers.

26. The element of claim 13 wherein said adhesive layer comprises one or more polymers selected from the group consisting of vinyl acetate, vinyl chloride, vinyl acetal, acrylic, and ethylene polymers and copolymers.

27. The element of claim 13 wherein said adhesive layer comprises one or more ingredients selected for the group consisting of plasticizers, uv absorbers, antistatic compositions, inert fillers, antihalation agents, and optical brighteners.

28. A method for producing an image which comprises:
(A) providing an electrophotographic color proofing element which comprises:
(i) a transparent support; and (ii) a transparent, electrically conductive layer on one side of said support; and (iii) a transparent, photoconductive layer on said conductive layer; and (iv) a colored photosensitive layer on the other side of said support; said colored photosensitive layer comprising at least one colorant, at least one photosensitive component, and at least one binder resin; said photosensitive component selected from the group consisting of polymeric diazonium salts, o-quinone diazides, and photopolymerizable compositions; said photopolymerizable compositions comprising both a photoinitiator and a free radical polymerizable component having at least one ethylenically unsaturated group; wherein said photosensitive component is present in sufficient amount to provide image differentiation when the composition is imagewise exposed to actinic radiation through said photoconductive layer, said conductive layer, and said support; wherein said colorant is present in an amount sufficient to uniformly color the layer; and wherein said binder resin is present in sufficient amount to bind the composition components into a uniform film; and (v) an optional adhesive layer directly adhered to said colored photosensitive layer, which adhesive layer comprises a thermoplastic resin which has a Tg in the range of from about 25°C to about 100°C; and (B) either (i) laminating at elevated temperature and pressure said electrophotographic element to a receiver sheet via the colored photosensitive layer or the optional adhesive layer; and electrically charging the photoconductive layer of said electrophotographic element; and imagewise exposing said charged photoconductive layer to radiation to which the colored photosensitive layer is not sensitive; and toning the photoconductive layer with a toner which is substantially opaque to actinic radiation used to expose said colored photosensitive layer; and optionally fixing at elevated temperature the imaged toner on said photoconductive layer; and exposing said colored photosensitive layer to actinic radiation through the toned photoconductive layer, conductive layer, and support; or (ii) electrically charging the photoconductive layer of said electrophotographic element; and imagewise exposing said charged photoconductive layer to radiation to which the colored photosensitive layer is not sensitive; and toning the photoconductive layer with a toner which is substantially opaque to actinic radiation used to expose said colored photosensitive layer; and optionally fixing at elevated temperature the imaged toner on said photoconductive layer; and exposing said colored photosensitive layer to actinic radiation through the toned photoconductive layer, conductive layer, and support; and laminating at elevated temperature and pressure the imaged electrophotographic element to a receiver sheet via the exposed colored photosensitive layer or the optional adhesive layer; and (c) peeling off the support along with the toned photoconductive layer, conductive layer, and nonimage areas of the colored photosensitive layer, leaving the image areas of the colored photosensitive layer and the optional adhesive on the receiver sheet.

29. The method of claim 28 further comprising optionally repeating steps (A) through (C) at least once wherein another electrophotographic element according to step (A) having at least one different colorant is laminated to the image produced from the previous electrophotographic element.

30. The method of claim 28 wherein the exposing of the photoconductive layer is conducted with a laser.

31. The method of claim 28 wherein the exposing step of the photoconductive layer is conducted with visible light radiation.

32. The method of claim 28 wherein the exposing step of the photosensitive layer is conducted with ultraviolet light radiation.

33. The method of claim 28 wherein the said receiver sheet comprises paper, coated paper, or polymeric film.

34. The method of claim 28 wherein each lamination is conducted at a temperature of from about 60°C to about 120°C.

35. The method of claim 28 further comprising the subsequent step of providing a protective covering of the image on the receiver sheet.

36. A method for producing an image which comprises:
(A) providing an electrophotographic color proofing element which comprises:
(i) a transparent support; and (ii) a transparent, electrically conductive layer on one side of said support; and (iii) a transparent, photoconductive layer on said conductive layer; and (iv) a photopolymerizable composition layer on the other side of said support, which photopolymerizable layer comprises a photoinitiator, a free radical polymerizable component having at least one ethylenically unsaturated group, and a binder resin;
wherein said photoinitiator is present in sufficient amount to initiate the free radical polymerization of said polymerizable component upon exposure to actinic radiation through said photoconductive layer, said conductive layer, and said support; wherein said polymerizable component is present in sufficient amount to provide image differentiation when the composition layer is imagewise exposed to actinic radiation; and wherein said binder resin is present in sufficient amount to bind the composition components into a uniform film; and (v) a colored photosensitive layer on said photopolymerizable composition layer; said colored photosensitive layer comprising at least one colorant, at least one photosensitive component, and at least one binder resin; said photosensitive component selected from the group consisting of polymeric diazonium salts, o-quinone diazides, and photopolymerizable compositions; said photopolymerizable compositions comprising both a photoinitiator and a free radical polymerizable component having at least one ethylenically unsaturated group; wherein said photosensitive component is present in sufficient amount to provide image differentiation when the composition is imagewise exposed to actinic radiation through said photoconductive layer, said conductive layer, and said support; wherein said colorant is present in an amount sufficient to uniformly color the layer; and wherein said binder resin is present in sufficient amount to bind the composition components into a uniform film; and (vi) an optional adhesive layer directly adhered to said colored photosensitive layer, which adhesive layer comprises a thermoplastic resin which has a Tg in the range of from about 25°C to about 100°C; and (B) either (i) laminating at elevated temperature and pressure said electrophotographic element to a receiver sheet via the colored photosensitive layer or the optional adhesive layer; and electrically charging the photoconductive layer of said electrophotographic element; and imagewise exposing said charged photoconductive layer to radiation to which the colored photosensitive layer and photopolymerizable layer are not sensitive; and toning the photoconductive layer with a toner which is substantially opaque to actinic radiation used to expose said colored photosensitive layer and said photopolymerizable layer; and optionally fixing at elevated temperature the imaged toner on said photoconductive layer; and exposing said colored photosensitive layer and said photopolymerizable layer to actinic radiation through the toned photoconductive layer, conductive layer, and support;
or (ii) electrically charging the photoconductive layer of said electrophotographic element; and imagewise exposing said charged photoconductive layer to radiation to which the colored photosensitive layer and the photopolymerizable layer are not sensitive;
and toning the photoconductive layer with a toner which is substantially opaque to actinic radiation used to expose said colored photosensitive layer and said photopolymerizable layer; and optionally fixing at elevated temperature the imaged toner on said photoconductive layer; and exposing said colored photosensitive layer and said photopolymerizable layer to actinic radiation through the toned photoconductive layer, conductive layer, and support;
and laminating at elevated temperature and pressure the imaged electrophotographic element to a receiver sheet via the exposed colored photosensitive layer or the optional adhesive layer; and (C) peeling off the support along with the toned photoconductive layer, conductive layer, photopolymerizable layer, and nonimage areas of the colored photosensitive layer, leaving the image areas of the colored photosensitive layer and the optional adhesive on the receiver sheet.

37. The method of claim 36 further comprising optionally repeating steps (A) through (C) at least once wherein another electrophotographic element according to step (A) having at least one different colorant is laminated to the image on the same receiver sheet produced from the previous electrophotographic element.

38. The method of claim 36 wherein the exposing step of the photoconductive layer is conducted with a laser.

39. The method of claim 36 wherein the exposing step of the photoconductive layer is conducted with visible light radiation.

40. The method of claim 36 wherein the exposing step of the photopolymerizable layer and the photosensitive layer is conducted with ultraviolet radiation.

41. The method of claim 36 wherein the said receiver sheet comprises paper, coated paper, or polymeric film.

42. The method of claim 36 wherein each lamination is conducted at a temperature of from about 60°C to about 120°C.

43. The method of claim 36 further comprising the subsequent step of providing a protective covering of the image on the receiver sheet.